One Affiliate or More?

What is better, to use the same bammer over and over again on different pages or to put different banners on every single page?

I think it is nicer to post different banners on each page. Besides the positioning of the banners, the banner you select can also make a huge difference in the visitor deciding whether or not to click your banner. I also think it looks fresh to see something similar but different.

If I see the same banner on every page of a site I am visiting, I always get the feeling that the webmaster ran out of creative, but that is a personal opinion.

Instread of just banners, try some text links. They are more clickable and you could change around the words for the same campaign.

Different banners with a TEXT link. Have the text link go to an internal page of a matching item. So be detailed. For example... Jewelry vs. Diamond Tennis Jewelry Bracelet - the more detailed the more buyers.

you want to decide what provides the greatest ROR and what's nice to the users. multiple banners may be it.

If i picked Amazon affiliate..... how does it work? Is it a good partner if i put banner on top of my website (every page)?

Amazon has a Very very low $. If you are looking for a no brainer just put up adsense. Then you don't have to choose a program. Otherwise pick a program that has a higher $ per action.